Fluid contacting apparatus

ABSTRACT

AN APPARATUS FOR CONTACTING TWO FLUIDS IN A FLUID-SOLIDS CONTACTING ZONE, SUCH AS ADSORPTION ZONE OR A REACTION ZONE. A FIRST FLUID IS PASSED INTO A CENTRAL CHAMBER HAVING A PLURALITY OF FLUID OPENINGS IN THE CHAMBER WALL, WHILE A SECOND FLUID IS PASSED INTO AN ANNULAR CHAMBER ENCOMPASSING THE CENTRAL CHAMBER AND SPACED APART THEREFROM. THE SECOND FLUID IS DISCHARGED VIA FLUID OPENINGS IN THE INNER ANNULAR CHAMBER WALL, INTO AN ANNULAR SPACE BETWEEN THE CHAMBERS, AND THE FIRST FLUID IS DISCHARGED FROM THE CENTRAL CHAMBER INTO THE SECOND FLUID DISCHARGE. A RESULTING FLUID MIXTURE IS PASSED FROM THE ANNULAR SPACE INTO A SECOND CHAMBER OR CONDUIT FOR FURTHER MIXING AND THEN TO A BED OF PARTICULATED CONTACT SOLIDS. SPECIFIC APPLICATION IS HYDROGENATION, HYDROTREATING, HYDROCRACKING, AND HYDRODEALKYLATION REACTION ZONES.   D R A W I N G

March 27, 1973 D. B. CARSON ET AL 3,723,972

FLUID CONTACT ING APPARATUS 3 Sheets-Sheet 1 Filed March l2,

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FLUID CONTACT ING APPARATUS 3 Sheets-Sheet 2 Filed March 12, 1971 Figur@/N VE/i'V TORS: Don B. Carson Wil/iam l?. Hannemufh A TTOR/VEYS March27, 1973 D. B. CARSON ET Al- 3,723,072

FLU ID CONTACT I NG APPARATUS Filed March l2, 1971 3 Sheets-Sheet 5F/gure 7 Figur@ 9a /uf L :V: I [V3/ 40 Second /n Second i /39 Figure 9cSecond Figure 8b F/rs Flow 39 40 Fg We 9d Mixtur 0uf F ig are 8c /N VENTORS: Don B. Carson Wil/iam R. Hannamuh www A TTRNE'YS Umted StatesPatent O U.S. Cl. 23-288 R 32 Claims ABSTRACT OF THE DISCLOSURE Anapparatus for contacting two fluids in a fluid-solids contacting zone,such as an adsorption zone or a reaction zone. A first fluid is passedinto a central chamber having a plurality of fluid openings in thechamber wall, while a second fluid is passed into an annular chamberencompassing the central chamber and spaced apart therefrom. The secondfluid is discharged via fluid openings in the inner annular chamberwall, into an annular space between the chambers, and the first fluid isdischarged from the central chamber into the second fluid discharge. Aresulting fluid mixture is passed from the annular space into a secondchamber or conduit for further mixing and then to a bed of particulatedcontact solids. Specific application is hydrogenation, hydrotreating,hydrocracking, and hydrodealkylation reaction zones.

CROSS-REFERENCE TO RELATED APPLICATION This application is acontinuation of our copendiug application, Ser. lNo. 835,449, filed June23, 1969, now U.S. Pat. No. 3,598,541, issued Aug. 10, 1971.

BACKGROUND OF THE INVENTION The present invention related to anapparatus for contacting two fluids in a fluid-solids contacting zonesuch as an adsorption zone or a reaction zone. More particularly, theinvention is directed to the contacting of two fluids comprising aliquid phase and a vapor phase in a fluid-solids contacting zone, and tomeans for effecting improved heat exchange between the vapor and liquidphases in the contacting vessel. More specifically, the presentinvention relates to a new and improved apparatus for uniformlydistributing mixed phases of vapor and liquid to a granular orparticulated solids contacting zone, as in an adsorption tower or as ina catalytic reactor such as a hydrogenation, hydrotreating,hydrocracking, or a hydrodealkylation reactor.

Among the most important of the various commercial processes are thoseinvolving the physical or chemical treatment of hydrocarbons and otherorganic materials with bodies of granular or particulated solid contactmaterials. Many of these processes involve the contacting of two fluidswith the contacting material, and most often, the two fluids comprise aliquid phase and a gas or vapor phase. It has been the experience in theart, that the introduction of mixtures of liquid and vapor into a bed ofparticulated contact solids in a uniformly distributed manner isdifficult to achieve.

Typical of the art wherein uniform distribution of liquid and gas phasesis necessary but infrequently achieved, is that of catalytichydrotreating and catalytic hydrocracking of various hydrocarbon oils.It is well known that the feed to such a reaction zone comprises aliquid hydrocarbon, a vaporized hydrocarbon, and a hydrogen-rich gas,and that this feed is introduced into the reaction zone at an elevatedtemperature. It is further known that the reactions which areencountered in this catalytic environ- Patented Mar. 27, 1973 ICC mentare exothermic, and that the temperature of the vapor phase and of theliquid hydrocarbon phase is increased due to the exothermic heat ofreaction. In order to avoid excessive temperature within the catalystbed it is typical to arrange the catalyst in a plurality of separate,superimposed fixed beds so that diluent or quench vapors may bedistributed between the lbeds during the reaction. The cool quenchvapors, normally comprising hydrogenrich gas, reduce the temperature ofthe efiluent from the bed above before the liquid-vapor mixture ofhydrocarbon and hydrogen is passed into the bed of catalyst below.

It is typical in the art to support each individual bed of catalyst upona perforated support plate. It is also typical in the art to introducethe quench hydrogen between the fixed beds of catalyst by means of aperforated pipe grd or other means which is positioned throughout thecrosssection of the reactor vessel at the quench point. The effluentfrom the catalyst bed above thus rains down from the perforated supportplate throughout the crosssectional area of the reactor while the quenchhydrogen is distributed by the perforated grid throughout thecross-sectional area of the reactor.

This prior art type of fluid distributing apparatus cornprising aperforated catalyst support plate and a hydrogen quench griddistributor, is utilized with the intent of achieving a completedistribution of liquid and gas phases as unformly as possible throughoutthe cross-sectional area of the reactor vessel and of the catalyst bedbelow. It is also the purpose of this typical fluid distributingapparatus to provide an intimate contact between hot effluent from thebed above and cool quench in order to achieve a uniform temperature ofthe constituents that pass into the bed below.

However, this typical prior art design has proven to be relativelyineffective in completely accomplishing these objectives. The problem iscomplicated by the fact that it is normal to add a relatively smallamount of cool quench hydrogen to a large quantity of hot eflluentcomprising hydrocarbon and hydrogen which is leaving the lbed above atan elevated temperature. The problem is additionally complicated by thefact that the amount of cold quench material is relatively small inrelation to the large cross-sectional area across which it must bedistributed in order to maintain a proper uniform distribution of liquidand vapor to the bed of catalyst below.

Further, because there is a mixed-phase condition within the reac-toritself, the heavier viscous liquids tend to channel down the side of thereactor whereas the less viscous liquids tend to channel in the centralregion of the catalyst bed with the vaporized hydrocarbon and hydrogen.The result is that the temperature encountered within the catalyst bedwill be quite uneven and localized undesirable hot spots are often foundin each bed. It is well known by those skilled in the art that theexistence of hot spots within the catalyst bed leads to undesiredindiscriminate or non-selective hydrocracking of the hydrocarbonconstituents.

Since the more viscous liquid tends to rain down through the 'supportplate near the walls of the reactor, these viscous materials will alsocontinue to channel along the walls in the beds below. This results inan ineffective quench between the beds, and the resulting continuationof liquid channeling produces additional danger of localized hot spotsin the lower catalyst beds.

'SUMMARY OF THE INVENTION distributing mixed phases of vapor and liquidin such contacting zones. It is a further object of this invention toprovide a lluid distribution means whereby a greatly improved contact ofvapor and liquid phases occurs at their point of introduction into asolid contacting zone. It is a still further object of this invention toprovide a means of improved heat exchange between a liquid phase and avapor phase passing to a lluid-solids contacting zone in a uniformlydistributed manner at a substantially uni form temperature.

These and other objectives and the advantages of the present inventionwill become more readily apparent to those skilled in the art as thesummary of the invention is more fully set forth hereinafter.

In the present invention, these objectives are achieved by the use of anovel combination catalyst support and ellluent redistribution apparatuswherein there is incorporated a novel means for injecting the quenchhydrogen into the efliuent which passes from the catalyst bed above tothe catalyst bed below.

One embodiment of the invention is clearly set forth in FIG. 1 whereinthere is illustrated a partially cut-away elevational view of a typicalhydrocracking reactor vessel containing a plurality of catalyst bedssupported upon the novel catalyst support and fluid distributionapparatus.

FIGS. 2 and 3 comprise sectional elevational views of the inventivecatalyst support and lluid distribution apparatus wherein the elementscomprising the apparatus are clearly set forth with particularity. Thesetwo embodiments comprise the inventive apparatus in a most simplifiedcombination of the elements.

FIGS. 4 through 6 comprise a particularly preferred embodiment of theinventive lluid distribution and contacting apparatus. FIG. 4 is asectional elevational view of the apparatus while FIGS. 5 and 6 comprisesectional plan views of the apparatus shown in FIG. 4.

FIGS. 7 and 8a through 8c illustrate a preferred embodiment of thecatalyst support plate which comprises one element of the lluiddistributing apparatus.

FIGS. 9a through 9d comprise simplified schematic flow diagrams whichillustrate the manner in which the inventive lluid distribution andcontacting apparatus may be operated.

In one preferred embodiment of the present invention, as applied to adownilow catalytic reaction zone, the lluid distribution and contactingapparatus comprises a catalyst support plate for holding and retainingthe catalyst bed above. The support plate comprises a perforated annularsection surrounding and encompassing a 'substantially imperforate centersection. Attached below the perforate annular section of the catalystsupport plate is an annular chamber containing a plurality of lluidopenings in the inner annular chamber wall. It is preferred that thissection be free of any particulate solids. Attached below thesubstantially imperforate center 'section of the catalyst support plateis a substantially confined central chamber having a plurality of lluidopenings in the chamber Wall. The annular chamber encompasses thecentral chamber and is spaced apart therefrom in a manner sufficient toprovide a confined annular space between the chambers having a lluidopening therein. Below the central chamber is a second chambercommunicating with the annular 4space between the central chamber andthe first annular chamber via the lluid opening in the confined annularspace. Preferably, this chamber comprises a first conduit means having aclosed end spaced apart from the lluid opening in the annular space, anopen end in communication with that opening, and a lluid opening in theconduit wall. Spaced around the first conduit is a seco-nd conduitclosed at both ends and also having a lluid opening in ythe conduitwall. `lreferably the lluid openings in the respective conduits aredisaligned.

In operation of the inventive combination catalyst support and fluiddistribution or contacting apparatus of the present invention in edewnllcw reaction zone. the 'eluent from the catalyst bed above passesthrough the perforated annular section of the catalyst support plate andinto the annular chamber below. Quench hydrogen is introduced by conduitmeans into the central chamber attached below the imperforate centersection of the catalyst support plate. The hot efliuent is dischargedinto the annular space via the lluid openings contained in the innerannular wall of the annular chamber. Simultaneously, the quench hydrogenis discharged into the annular space via the iluid openings in thechamber wall of the central chamber. Prefer-ably, the effluentdischarged and the quench hydro gen discharged impinge upon one anotheraxially in order to produce a region of high turbulence within theannular space and thereby produces a homogeneous mixture ofsubstantially uniform temperature. The mixture of quench hydrogen andcooled ellluent then passes from the annular space into the described,second chamber below for further mixing and is then discharged to thecatalyst bed below.

A clear understanding of the present invention may now be obtained byreferring to the accompanying figures.

DESCRIPTION OF THE FIGURES As noted hereinabove, one particularlypreferred embodiment wherein the apparatus of the present inventionfinds application is in exothermic hydrocarbon conversion processingover particulated conversion catalyst. For illustrative purposes thedrawing of FIG. l shows an embodiment of the invention wherein ahydrocarbon fraction is hydrocracked in the presence of hydrogen over asuitable hydrocracking catalyst.

FIG. l shows a simplified partially cut-away elevational view of ahydrocracking reactor vessel comprising a vertically elongated shell 1having a fluid inlet nozzle 2 at the top of the shell and a fluid outletnozzle 3 at the bottom of the shell. Reactor vessel 1 contains threecatalyst beds, beds A through C, supported upon the inventive catalystsupport and lluid distribution apparatus. Attached to the reactor shell1 there are also provided hydrogen quench ports 4. At the bottom ofreactor shell 1 and covering the lluid opening 3 is a screen device 5which supports the bottom catalyst bed, bed C.

The catalyst beds contain a typical hydrocracking catalyst which may bepresent in pilled, spherical, or extruded form. The particulatedcatalyst particles 7 are supported upon a layer of inert supportmaterial 6. The support material 6 may comprise ceramic balls, Berlsaddles, Raschig rings or any other inert packing material which istypically used in hydrocarbon conversion reactors for supporting beds ofparticulated catalyst. In addition, each lbed contains a similar layerof inert support materials 8 at the top of the catalyst particles 7.This upper layer of inert support material is used as a means forholding down the low density particles of catalyst 7 in case of pressurefluctuation, and for enhancing distribution of fluids which enter thetop of each bed.

Each entire upper catalyst bed (beds A and B) comprising catalystparticles 7, lower support layer 6, and covering layer `8 is supportedupon a catalyst support plate member or deck which comprises aperforated annular section 9 encompassing a substantially imperforatecenter section 10. For illustrative purposes, perforated annular section9 is shown as a Woven screen section. Attached below the imperforatecenter section 10 is a central chamber 11 having a plurality of lluidopenings 12 in the vertical wall. Centrally disposed in the imperforatecenter section 10 is a lluid inlet port 13 which provides for the flowof quench hydrogen into the central chamber 11 from hydrogen quenchnozzle 4 via conduit means 17.

Attached to the catalyst support plate member is an annular chamber 14which comprises as its upper chamber wall the perforated annular section9 of the catalyst support plate. Annular chamber 14 contains a pluralityof lluid openings 15 in the inner annular wall of the chamber. Annularchamber 14 encompasses central chamber 11 and is spaced apart therefromin a manner sufllcient to provide an annular space 16 between thechambers. Attached to the `annular chamber below the central chamber 11and below the annular space 16 is a perforated means 18.

'In the typical hydrocracking process, a feed comprising liquidhydrocarbon, vaporized hydrocarbon, and a hydrogen-rich gas enters thereactor vessel 1 via inlet nozzle 2. This feed mixture passes throughthe rst catalyst bed A and is increased in temperature due to thehydrocracking reaction which occurs therein. As the feed and resultingeffluent pass through catalyst bed A, the vapor portion will typicallytend to flow down the central region of the catalyst bed while theliquid portion will tend to channel down the reactor walls and along theouter regions of the catalyst bed. The liquid and vapor portions, uponpassing through the catalyst bed, enter the annular chamber 14 throughthe fluid passageway which is provided by the perforated annular section9 of the catalyst support plate. Annular chamber 14 provides a reservoirwithin which channeling liquids may be remixed to provide a relativelyhomogeneous liquid hydrocarbon phase and to eliminate the concentrationeffects which occur due to the channeling of liquid in the catalyst bedabove. Therefore, as illustrated, it is preferred that chamber 14 berelatively free of solids. The hot elluent comprising liquidhydrocarbon, vaporized hydrocarbon, and hydrogen-rich gas is dischargedfrom the annular chamber 14 into the annular space 16 via fluid openings15.

Simultaneously, quench hydrogen enters the reactor via hydrogen ports 4and passes into the central chamber 11 via conduit means 17 and inletport 13. The cool quench hydrogen is discharged into the annular space16 via fluid openings 12. Preferably, fluid openings 12 are insubstantially axial radial alignment with iluid openings 15 so that thehydrogen quench discharge passes directly into the hot effluentdischarge to provide a region of high turbulence within annular space16. The resulting mixture of eflluent and quench hydrogen leaves theannular space 16 at a substantially uniform temperature and passesthrough perforated means 18 into the catalyst bed B below. Perforatedmeans 18 is provided below annular space 16 in order to provide anadditional means of redistributing the resulting mixture in a moresubstantially uniform pattern as it falls through space 19 into thecatalyst bed B below.

The mixture passes through bed B and is elevated in temperature byadditional hydrocracking reaction. The resulting eilluent comprisingliquid and vapor is quenched with additional cool hydrogen in thecatalyst support and fluid distributing or contacting apparatus which ispositioned below and supports catalyst bed B. The resulting mixture ofquench hydrogen and eilluent liquids and vapors passes from theinventive fluid distribution and contacting apparatus into catalyst bedC at a substantially uniform temperature and in a substantially uniformdistribution. Additional hydrocracking reaction occurs in catalyst bed Cand the total final mixture of hydrocarbon liquid, hydrocarbon vapor,and hydrogen-rich gas passes out of the reactor via support means andiluid outlet port 3. The effluent is then separated in a manner that iswell known to those skilled in the art for recovery of the desiredhydrocarbon products.

FIG. 2 illustrates typical elements comprising the inventive catalystsupport and iluid distribution or contacting apparatus of FIG. l asshown in vertical section. Referring now to FIG. 2, there is shown aportion of the reactor shell l and attached thereto a support ring 20for holding and retaining the inventive apparatus. For ease indiscussion, the catalyst bed above is not shown in the drawing.Supported upon support ring 20 is a lower support plate 21 having acentral hole 22. Support plate 21 thus has an annular configuration andprovides the floor or bottom wall for the annular chamber 14. Risingvertically above support plate 21 and adjacent to the reaction shell isa support skirt 23. This support skirt 23 provides the outer annularwall of the annular chamber 14. Also rising above support plate 2i1adjacent to the central hole 22 is the inner annular wall 24 of theannular chamber 14. The inner annular wall 24 contains a plurality offluid openings 15 which provide communication between annular chamber 14and annular space 16.

The upper support plate member or deck of the inventive apparatus, asnoted during the discussion of FIG. 1, comprises a perforated annularsection l9 and a substantially imperforate center 101. The perforatedannular section 9 provides the roof or top wall of annular chamber 14and simultaneously provides the means or passageway for the flow ofeffluent from the catalyst bed above (not shown) to the annular chamber14.

Attached to the bottom of the imperforate center section 10 is a centralchamber 111 formed by the vertical wall 25 and a bottom wall 26 attachedthereto. The wall 25 of the central chamber contains a' plurality offluid openings 12 which provide communication of the central chamberwith the annular space 16. The center of the imperforate section of theupper support plate contains the fluid port 13 which provides an inletmeans for the introduction of quench hydrogen as noted in the discussionrelative to FIG. 1.

In the embodiment shown in FIG. 2, in addition to the annular space 16between the central chamber 11 and the annular chamber 14, there isprovided a space 27 located below the central chamber and aboveperforated means L18 which covers hole 22 in the lower support plate 21.The space 27 and perforated means 18 enhance the redistribution offluids which pass out of the annular space 16 so that the vapor-liquidmixture flowing through the perforated means 18 is more uniformlydistributed on the upper surface of the catalyst bed below.

While the preferred embodiment of FIG. 2 comprises the circularperforated means 18 below the central chamber 11, a further embodimentof the apparatus of FIG. 2 may be provided. In this alternateembodiment, the central chamber 11 would be extended downwardly so thatthe bottom plate 26 thereof would be on the same plane as the lowersupport plate 2.1. This then would provide that the lower space 27 wouldbe eliminated and that the annular space 16 would extend all the way toopening 22 in lower support plate 21. The perforated means 18,therefore, would be annular perforated means and not necessarily acircular perforated means.

A further embodiment of the apparatus shown in FIG. 2 is provided bychanging the hydrogen quench passageway from the central chamber to theannular chamber as illustrated in sectional elevation in FIG. 3. Theelements of FIG. 2` are again repeated in the construction of theapparatus shown in FIG. 3, with several modifications, however. Bycomparing FIGS. 2 and 3, it will be seen that 1n the embodiment of FIG.3, the hydrogen quench nozzle 4 1s in communication with the annularchamber 14 by means of a fluid opening 28 which is provided in the wallof the reactor shell 1 and in the support skirt 23 which forms the outerwall of the annular chamber 14. In addition, the upper support platemember or deck which holds and retains the catalyst bed, not shown,comprises an imperforate annular section 29 encompassing a perforatedcenter section which comprises a hole 30 in the support plate 29 and aperforate means 31 covering this hole.

The apparatus disclosed in FIG. 3 will function in the manner which hasbeen set forth hereinabove in discussing FIG. l, notwithstanding thatthe apparatus of FIG. 3 provides for the eilluent to pass into thecentral chamber 11 while the hydrogen quench passes into the annularchamber 14. In the embodiment of FIG. 3 the effluent will pass into theannular space 16 via fluid openings 12 while the quench hydrogen passesinto the annular space 116 via fluid openings 15. The two fluids meet inthe annular space 16 to create a zone of turbulence wherein they arethoroughly mixed. The mixture is then discharged downwardly from theannular space 16 to the catalyst bed below via opening 22- andperforated means 18.

In the embodiments shown in FIGS. l through 3, it is preferred that thecentral chamber 11 have a cylindrical configuration. It is alsopreferred that the plurality of fluid openings 12 be radially spaced ina substantially uniform manner in the cylindrical wall 25. The fluidopenings 12 may be oriented so that discharging lluid passes through theopenings 12 and impinges on the Wall 24 of the annular chamber in amanner sufcient to provide turbulence within the annular space @16.Additionally, the fluid openings 15 preferably are radially spaced in asubstantially uniform manner in the inner annular wall 24 of the annularchamber 14. Fluid openings 15 may be oriented in a manner sucient toprovide that the discharging fluid will impinge upon the wall 25 of thecentral chamber 11 in a manner sufficient to provide turbulence withinthe annular space 16. However, it is a preferred embodiment that thefluid openings 12 and 15 be equal in number and in substantially axialradial alignment in order that the discharging fluid passing throughopening 12 impinges upon the discharging iluid passing through opening15 so that the two fluids are given a most direct and forceful mixingeffect within the annular space `16.

The fluid distributing or contacting apparatus which has beenillustrated in FIGS. 2 and 3 comprises only two embodiments of thepresent invention. In FIGS. 4 through 6 there is shown a particularlypreferred embodiment of the inventive apparatus as applied to a largediameter iluid contacting Vessel. FIG. 4 provides a sectionalelevational view of this alternate preferred embodiment. FIGS. 5 and 6provide sectional plan views of the alternate embodiment of FIG. 4.

Referring now to FIG. 4 there is shown a portion of the verticallyelongated shell 1 and the support ring 20. The lower support plate 21having a central opening 22 is held upon this support ring 20. Thesupport skirt 23 which was provided in the embodiments of FIGS. 2 and 3is not so provided in this embodiment, and the required support of theupper plate or deck retaining the catalyst bed is provided by bearingbeam members in a manner disclosed hereinafter. However, there is shownthe inner annular wall 24 of the solids-free annular chamber 14. Theinner annular Wall 24 supports the center imperforate section 10. Theimperforate section has the lluid inlet port 13 centrally disposedtherein. Below the imperforate section 10 is the central chamber 11comprising the chamber wall 25 and the chamber bottom plate 26. Thechamber wall 25 contains the plurality of fluid openings 12.

Extending radially from the inner annular chamber wall 24 to the reactorshell 1 is a plurality of support beam members 32 which divide annularchamber 14 into a plurality of annular sectors. Each support beam member32 preferably contains a plurality of uid openings 33 in order that theannular sectors formed by the support beam member 32 are in iluidcommunication with each other. Beam members 32 are shown as having aplate configuration, but they may have any crosssectional shape such asan angle, T, channel, I-beam, or other configuration. The support beammembers 32 support the perforated annular section 9 of the upper supportplate member or deck which retains and holds the catalyst bed above. Theperforated annular section 9 has a preferred construction to bedisclosed in FIGS. 7 and 8a through 8c hereinafter.

FIG. 5 provides a sectional plan View of the inventive iluiddistributing and contacting apparatus of FIG. 4

as taken along line 5 5. In FIG. 5, there is shown the reactor shell 1and the inner annular Wall 24 of the annular chamber 14. There is alsoshown the cylindrical wall 25 of the central chamber 11. The innerannular Wall 24 contains the plurality of fluid openings -15 which aredisposed therein in a substantially axially radial alignment with theplurality of tluld openings 12 in the 8 wall 2'5 of central chamber 11.FIG. 5 also shows the annular space 16 which is provided between the twochambers, as well as lower support plate 21 and the bottom plate 26.

It will be seen clearly in FIG. 5 that the annular chamber 14 is dividedinto a plurality of annular sectors by the bearing beam members 32. Itis also apparent that each annular sector contains one fluid opening 15,although those skilled in the art realize that more than one iluidopening 15 may be provided in any annular sector. There is also shown inFIG. 5 the plurality of fluid openings 33 within each support beammember 32. Thus, it is readily ascertainable to those skilled in the artthat the annular chamber 14 is divided into a plurality of annularsectors by the support beam members 32 which support the perforatedannular section 9 of the upper support plate.

It is further apparent from FIGS. 4 and 5 that the annular sectors ofannular chamber 14 are in iluid communication with each other by meansof the Huid openings 33 in the support beam members 32. Thus, if efuentchanneling down from the catalyst bed above does so in a manner whichcauses liquid to be concentrated in one area of the annular chamber,this concentrated liquid will be redistributed to the adjacent annularsectors of the annular chamber 14 Via uid openings 33. It is thuspreferred that annular chamber 14 be solids-free since the presence ofsolids would hinder the mixing of fluids entering chamber :14 atopposite points on the perimeter. Fluid openings 33 thus provide for amore uniform distribution of eluent liquids which are thereafterdischarged from the annular chamber 14 into the annular space 16.

Referring now again to FIG. 4, there is shown the annular space 16between the annular chamber 14 and the central chamber 11. There isadditionally shown the open space 27 below the central chamber 11 andabove the iluid opening 22 in the lower support plate 21. It will beseen in FIG. 4 that the annular configuration of the imperforate lowersupport plate 21 is such as to provide a bailling effect to the flow offluids within annular space 16 and open space 27. The diameter of thefluid opening 22 in the lower support plate 21 is smaller than thediameter of the central chamber 11. Therefore, the fluid mixture owingdownwardly from the annular space 16 is baffled horizontally to thecenter for subsequent downward passage through the fluid opening 22 andthereby given a further mixing effect. Below the lower support plate 21there is provided a further series of vertical baffles 34 and 35 connedbetween the lower support plate 21 and a bottom baille plate 36.Vertical baes 34 and 35 from chamber 42 and are attached via supportplate 21 to annular chamber 14. Within chamber 42 the fluids previouslymixed in annular space 16 enter via fluid* opening 22 and are furthermixed before being discharged via vertical slot openings v43 formed bybaffles 35. As illustrated in FIGS. 4 and 6, vertical baffles 34 areformed by a conduit having a pair of continuous vertical slots 45parallel to the axis of the conduit. Similarly, baffles 35 are alsoformed by a conduit which is spaced around and apart from baffles 35 andforms annular space 44. Preferably, slot openings 43 and 45 aredisaligned to enhance fluid mixing. Annular space 44 is closed at thetop by support plate 21 and at the bottom by baffle plate 36. Attachedto the baffle plate 36 is an annular perforate section 37 supported upona support ring 38 attachedto the reactor shell 1.

Referring now to FIG. 6, there is shown a sectional plan view of theapparatus of FIG..4 taken along the line 6--6 in order to more clearlyshow the construction of the battles below fluid openings 22 and howthey relate to form chamber 42 and annular space 44. In FIG. 6, there isshown the reactor shell 1 and the bottom baffle plate 36. Confinedbetween the reactor shell -1 and the bottom baille plate 36 is theannular perforate section 37. From FIG. 6, it will be seen that thevertical baliles 34 and 35 formed by slots 43 and 45 in the describedtwo conduit means positioned between the lower support plate 21 and thebottom baille plate 36 have a relatively concentric semi-circularconfiguration. The pair of outer baffles 35 formed along the outerperiphery of bottom baille plate 36, have an opening 43 between each endof the battles 35. Contained within formed outer batlles 35 is a pair offormed inner baffles 34 oriented to give a tluid opening 45 between theends of baflies 34 which is 90 from the iluid opening 43 between theends of the outer baffles 35. Thus, fluid passing downwardly from tluidopening 22 into chamber 42 impinges upon the bottom baille plate 36 andis conducted horizontally through the openings 45 between the ends ofbafiles 34. The fluid then passes circumferentially between battles 34and 35 through annular space 44 and is then discharged from opening 43between the ends of baffles 35. The passage of the fluids in theconfined annular path 44 between baffles 34 and 35 provides added mixingdue to the turbulence therein. The discharged fluids comprising, in theillustrative example of FIG. 1, liquid hydrocarbon, vaporizedhydrocarbon, and hydrogen gas, is then distributed by means ofperforated annular section 37 to the catalyst bed below, not shown, in asubstantially uniform manner throughout the entire cross-section of thebed.

As noted, the inventive catalyst support and iluid contacting apparatusillustrated in FIGS. 4 through 6 has particular utility in contactingvessels of large diameter. The support beam members 33 are radiallydisposed in order to support perforated annular section 9, and in orderto give structural strength to the contacting apparatus. Those skilledin the art will ascertain that the outer support skirt 23, which wasshown in FIGS. 2 and 3, could additionally be employed in thisembodiment. The sequence of bafes formed by a slotted conduit which isprovided in the preferred embodiment shown in FIGS. 4 and 6, and theannular perforate section 37 are provided in order to give increasedturbulence and mixing of the fluid before they are redistributed acrossa large cross-sectional area in a large diameter contacting vessel. Theannular perforate section 37 is provided in order to maintain asufficient pressure drop so that the fluid mixture will be distributedacross the entire cross-sectional area of the reactor and notconcentrated in the center as could otherwise occur without perforatemeans 37.

FIGS. 7 and 8in through 8c illustrate a preferred embodiment for theperforated annular section 9 of FIGS. 1, 2, and 4, and for theperforated center section 31 of FIG. 3. The perforate sections whichhave been illustrated in the figures are shown as a woven screen means,with the exception of FIG. 4 wherein there is shown a specialconstruction for the perforated annular section 9. This preferredconstruction for the annular section 9 and for the center section 31comprises a perforated section constructed by spacing a plurality oflongitudinal rod members transversely upon bearing rod memberssufllcient to provide a plurality of slot openings.

Referring now to FIG. 7, there is shown in plan view a portion of theperforated annular section 9 of FIG. 4. A plurality of longitudinal rodmembers 39 are supported upon and attached to a plurality of bearing rodmembers 40 in a manner suilicient to provide a slot opening 41 betweenadjacent longitudinal rod members 39. The longitudinal rod members 39are spaced a finite distance apart so that slot opening 41 will passiluids while retaining particulated contact solids of the size normallyemployed in a catalytic reactor bed. While FIG. 7 shows the longitudinalrod members 39 aligned perpendicular to the bearing rod members, thoseskilled in the art will realize that the bearing rod members 40 couldhave a radial alignment so that the longitudinal rod member 39 would 10be attached transversely to the bearing rod member 40, but notperpendicular thereto.

FIGS. 8a through 8c illustrate sectional views of the perforated section9 illustrated in FIG. 7 taken along the section line 8 8. In FIG. 8a,there is shown a bearing rod member 40 supporting a plurality oflongitudinal rod members 39. The adjacent longitudinal rod members 39have a circular cross-sectional area in FIG. 8a. Thus, it may be notedthat the cross-section of the resulting slot opening 41 has a convergingconfiguration in the direction of tluid tlow so that the slot becomesnarrower at the diameter of the adjacent rod members 39. Thus, anyparticulated solid such as catalyst fines may become lodged in the slot41 and blind a portion of the perforated section 9 (or 31).

It is, therefore, a preferred embodiment that the longitudinal rodmember 39 have a triangular or wedgedshape cross-section as shown inFIGS. Sib and 8c. By having the wider portion of the wedged-shapecross-section of the rod member 39 along the outer surfaces of theperforated section 9 or 31, the slot opening 41 is thereby provided withan increasing size fluid passageway for the tlow of iluid, and once anyentrained particulated matter such as catalyst fines passes into theslot opening 41, it can more readily pass downwardly and into thechamber below. Itt will be seen in FIGS. 8b and 8c that the slot opening41 also results in a triangular or wedgedshape cross-section for thisfluid passageway with the widest portion of the wedged-shape slotopening towards the inside surfaces of the perforated section. Thus, byemploying the triangular or wedged-shape cross-section coniiguration forrod member 39, the perforated section 9 or 31 is a self-cleaning typescreen section since retention of the solids and blinding of the screenis minimized.

FIG. 8b specifically illustrates the cross-sectional area of alongitudinal rod member 39 having a solid trapezoidal shape. FIG. 8cillustrates a channel type crosssection wherein the open end of thechannel is narrower than the flange end of the channel thereby providingthe desired wedge-shaped. For screens of the general type shown in FIGS.8b and 8c, reference may be made to U.S. Pats. 2,046,456; 2,046,457;2,046,458; and 3,101,526.

FIGS. 9a through 9d comprise simplified schematic flow diagramsdisclosing the manner of operation for the inventive fluid distributionand contacting apparatus. Although FIGS. 9a through 9d indicate themanner of operation for the apparatus as embodied in FIGS. l, 2 and 4,the teaching is equally pertinent to the manner of operation for theembodiment in FIG. 3.

FIG. 9a discloses a contacting method utilizing the apparatus of FIG. 2wherein the first tluid is passed downwardly into the central chamber 11and the second fluid is passed downwardly into the annular chamber 14.The two tluids then pass through the respective fluid openings and intothe annular space 16, wherein intimate contacting and mixing occurs. Aresulting mixture then passes downwardly from the annular space and intospace below. This is the preferred downilow method of operation whichhas been previously disclosed hereinabove.

FIG. 9b illustrates the operation of the inventive apparatus of FIG. 2in an uptlow manner. There is shown in FIG. 9b the irst fluid passingdownwardly into the central chamber 11 while the second fluid passesupwardly into the annular space 16 from the space below the inventivecontacting apparatus. The first iluid is passed through the tluidopening of the central chamber wall and into the annular space 16wherein iirst and second fluid are intimately contacted and mixed. Theresulting mixture then passes through the fluid openings of the i11- nerannular wall of the annular chamber 14 and then out of the annularchamber in an upflow manner.

Those skilled in the art will readily ascertain that the inventive fluidcontacting and distributing apparatus of the present invention will alsofunction upflow and downflow if the embodiments of the Iapparatus areinverted.

Thus, for example, FIG. 9c and 9d indicate the inventive apparatusillustrated in FIG. 2 wherein the apparatus has been turned upside down.

Referring now to FIG. 9c for downow operation, the first fluid is passedinto the central chamber 11 upwardly while the second fluid is passeddownwardly into the annular space 16 from the space above the apparatus.The first fluid passes from the fluid openings of the central chamberwall into the annular space 16 where it intimately contacts the secondfluid to produce a substantially homogeneous mixture. The resultingmixture passes into the annular chamber 14 via the fluid openings in theinner annular chamber wall of chamber 14. The mixture then passesdownwardly through the perforated means and is discharged from theannular chamber.

Referring now to FIG. 9d, there is shown the operation of the inventiveapparatus oriented in an upside down position for upliow fluidprocessing. In FIG. 9d, there is shown the first fluid passing into thecentral chamber 11 in an upflow manner while the second fluid passesinto the annular chamber 14 in an upflow manner. The first and secondfluids are discharged through their respective uid openings in thechamber walls into the annular space 16 wherein they are intimatelycontacted to produce a substantially homogeneous mixture. The mixturethen passes upflow from the annular space and is discharged from theinventive apparatus in the manner illustrated.

In comparing the operations which have been set forth in FIGS. 9athrough 9d as simplified flow diagram, those skilled in the art willperceive that the inventive fluid contacting apparatus may also beoperated backwards. That is to say, that the first uid could be passedinto the annular chamber 14 while the second fluid was passed into theannular space. The first fluid would then be discharged into the annularspace for mixing With the second fluid. The mixture would then pass intothe central charnber 11 via the fluid openings in the chamber wallthereof. The mixture would then pass out of the central chamber andcould be withdrawn by a conduit means or passed into a contactingsystem, not shown. Thus, in effect, the apparatus would be functioningbackwards since the central chamber would be an outlet passageway andnot an inlet passageway. However, this embodiment has not beenillustrated by schematic diagram herein, since it is not a particularlypreferred manner of operation.

PREFERRED EMBODIMENT From the foregoing disclosure it may be readilyascertained that in a preferred limited embodiment of the presentinvention the support plate member associated with the inventiveapparatus comprises a perforate annular section encompassing asubstantially imperforate center section; the confined central chamberattached to the support plate member comprises a central portion of theimperforate section, and has a plurality of first uid openings spaced inthe chamber wall; the annular chamber attached to the support platemember comprises the perforate annular section, spaced around and apartfrom the central chamber in a manner sufficient to provide a firstannular space within third uid opening, said space located between thechambers, and has a plurality of second fluid openings in the innerannular wall of the annular chamber; and fluid conduit means communicatewith the confined central chamber.

In a further preferred embodiment, the support plate member comprises aperforate center section encompassed by an imperforate annular section;the central chamber attached to the support plate member comprises theperforate center section, and has a plurality of rst fluid openingsspaced in the chamber wall; the confined annular chamber attached to thesupport plate member, comprises an outer annular portion of theimperforate annular section, spaced around and apart from the centralchamber in a manner sufficient to provide an 12 annular space betweenthe chambers, and has a plurality of second uid openings in the innerannular wall of the annular chamber; and liuid conduit means communicatewith the confined annular chamber.

Those skilled in the art realize that for optimum operation, a highpressure drop is necessary in order to provide maximum turbulenceresulting in optimum mixing and redistribution of the fluids. The highpressure drop may be produced by providing minimum diameters and aminimum number of the uid openings 12 and 15. In addition, the highpressure drop may be produced by providing a minimum distance betweenwall 25 of the central chamber and wall 24 of the annular chamber.

While maximum pressure drop is desirable from a standpoint of optimummixing and redistribution of the fluids, those skilled in the art willalso realize that minimum pressure drop is desirable from a structuralstandpoint. Thus, if a high pressure drop is produced by the dimensionaldesign of the inventive fluid contacting apparatus, a greater structuralstrength of the various elements of the apparatus must be provided inorder to keep the inventive fluid contacting means from collapsing dueto the pressure drop. Thus, the increased need for structural supportrequires a greater capital expense in fabricating the apparatus. Inaddition, those skilled in the art will realize that if a high pressuredrop is provided in the apparatus, a greater compressor capacity isArequired in order to provide the hydrogen quench which has beenillustrated as one'of the uids in the foregoing disclosure.

Thus, in summary, a high pressure drop, while providing optimumcontacting, mixing and redistribution of the fluids, will also result ina higher capital cost and in a higher utility cost in operating theapparatus in the manner disclosed. Those skilled in the art must,therefore, strike a balance between these competing considerations.

In addition it has been noted that the fluid openings 12 may be orientedso that they are positioned opposite an imperforate section of theannular wall 24. Additionally, the fluid openings 1S may be positionedso that they are opposite an imperforate section of the central chamberwall 25. In such an embodiment then it is preferred that the distancebetween wall 24 and wall 25 be minimized in order that the dischargedfluid streams may impinge upon the opposite wall with the greatest forcein order to produce a maximum amount of turbulence in the annular space16.

However, as noted hereinabove, the preferred embodiment for theinventive apparatus comprises the apparatus wherein the fluid openings12 and the fluid openings 1S are equal in number and in substantiallyaxial radial alignment. In this embodiment, it is preferred that thedistance between central chamber wall 25 and annular chamber wall 24 beminimized in order that the two fluid streams which are discharged fromtheir respective iuid openings may axially impinge upon each other witha maximum of force, in order to provide optimum contacting and mixing ofthe fluids in the annular space 16.

Thus, the dimensions of the inventive uid contacting and distributingapparatus, and the dimensions for the elements thereof cannot be setforth herein with great specificity since a great many factors willaffect the pressure drop and thus the dimensions which are required inan specific environment. Among the factors to consider in ahydrocracking reactor, for example, are the rate of ow of the effluentfrom the catalyst bed above to the catalyst bed below as well as therate of ow of the quench hydrogen. The distribution of the vapor andliquid phases of the effluent flowing from the bed above will alsoaffect the dimensions which are required in the design of the inventivecontacting apparatus, and the temperature and pressure of the effluentwill have a pronounced effect upon the distribution of vapor and liquidphases. In addition, it must be realized that the temperature at whichthe quench hydrogen is introduced will also have a pronounced effect onthe degree of thermal quench which is experienced and upon the pressuredrop which will be produced. Finally, molecular weights of the twofluids must be considered and the density of the various vapor andliquid phases is a primary consideration in dimensionally sizing thecontacting apparatus for optimum pressure drop in order to produce asubstantially uniform mixing of the two fluid streams.

Those skilled in the art will readily ascertain that the factors andconsiderations which have been recited hereinabove are of equalimportance in an upflow application of the apparatus as well as in adownflow application. Those skilled in the art can readily design theinventive apparatus for either upflow or downllow operation by utilizingthe teachings that have been presented herein.

While the embodiments disclosed hereinabove have been particularlydirected to the catalytic reaction of hydrocarbons in a hydrogenatmosphere, the invention is not so limited. Those skilled in the artWill perceive that the method of contacting two fluids in a fluid-solidscontacting zone and the apparatus, therefor have equal application inany fluid-solids contacting zone such as an adsorption zone as well as areaction zone. Additionally, the apparatus is not limited to the supportof fixed beds of particulated contact solids, but it can also findapplication, for example, as the feed distribution apparatus at the topof the first bed contained within a downflow contacting chamber or atthe bottom of the first bed contained within an upflow contactingchamber.

The method and apparatus also is not limited to the specific fluidsdisclosed relative to hydrocracking operation. Thus, the first fluid andthe second fluid illustrated in FIGS. 9a through 9d could individually`comprise a liquid phase, a vapor phase, or a mixture of liquid andvapor phase. Those skilled in the art will realize that the inventiveapparatus may have application where both fluid streams are liquidphases such as in a contacting operation in an extraction zone.Additionally, while the downflow embodiments of the inventive apparatusand the fluid contacting1 method have preferred application to fixedbeds of particulated solids, the upllow embodiments may be easilyadapted to fixed beds, lluidized beds, or ebullient beds.

However, from the disclosure hereinabove, it will be readily apparentthat the particularly preferred embodiment of the present inventioncomprises application of the inventive apparatus and contacting methodwherein the fluid-solids contacting chamber is a downflow catalyticreaction zone for the processing of hydrocarbon constituents in thepresence of hydrogen. Additionally, as noted hereinabove, specificapplication of the present invention is in downilow hydrogenation,hydrotreating, hydrocracking and hydrodealkylation reaction zoneswherein a hydrogen stream is utilized for the thermal quench of reactanthydrocarbon between catalyst beds.

We claim:

1. A fluid contacting means which comprises, in combination:

(a) a central chamber having a plurality of first fluid openings spacedin the chamber wall;

(b) an annular chamber spaced around and apart from the centnal chamberhaving a plurality of second fluid openings spaced in the inner annularwall of the chamber;

(c) means for attaching the central chamber to the annular chamber in amanner suflicient to space the annular chamber from the central chamberand to provide between the central chamber and the annular chamber afirst, confined annular space having communication with the first fluidopenings and second fluid openings and haivng a third fluid openingtherein;

(d) a first fluid passageway communicating with the central chamber;

(e) a second fluid passageway communicating with the annular chamber;

(f) a first conduit means having a closed end spaced apart from thefirst annular space, a fourth fluid opening in the conduit wall and anopen end in cornmunication with the third fluid opening in the confinedannular space;

(g) means for attaching the first conduit means to the annular chamber;

(h) a second conduit means closed at both ends and having a fifth fluidopening in the conduit wall, spaced around and apart from the firstconduit means; and

(i) means for attaching the first conduit to the second conduit in amanner sufficient to space the first conduit from the second conduit andto provide a second annular space between the conduits havingcommunication with the fourth fluid opening and fifth fluid opening.

2. The fluid contacting means of claim 1 wherein the first and secondfluid openings of the central and annular chambers are in substantiallyaxial alignment.

3. The fluid contacting means of claim 1 wherein the central chamber andthe annular chamber are cylindrical chambers and the first fluidopenings and second fluid openings are substantially uniformly spacedand are in substantially axial alignment.

4. The fluid contacting means of claim 1 wherein the annular chamber isdivided into a plurality of sectors with each sector containing at leastone of the second openings.

S. The fluid contacting means of claim 4 wherein each sector is incommunication with an adjoining sector.

6. The fluid contacting means of claim 1 wherein a perforate means isattached to the second conduit below the fifth fluid openings.

7. The fluid contacting means of claim 6 wherein the perforate meanscomprises an imperforate center section and a perforate annular sectionaround the center section.

8. The contacting means of claim 1 wherein the rst fluid passagewaycomprises third conduit means and the second fluid p-assageway comprisesperforate means.

9. The contacting means of claim 1 wherein the first fluid passagewaycomprises perforate means and the second fluid passageway comprisesthird conduit means.

10. The contacting means of claim 1 wherein the fourth fluid opening andthe fifth fluid opening comprise a slot parallel to the axis of eachconduit.

11. The contacting means of claim 1 wherein the fourth fluid opening andthe fifth fluid opening are disaligned.

12. The contacting means of claim 1 wherein the fourth fluid opening andthe fifth fluid opening each comprise a pair of slots parallel to theaxis of each conduit and are about disaligned.

13. A fluid contacting chamber which comprises, in combination (a) avertically elongated chamber having at least one upper fluid port andone lower fluid port to provide for a generally vertical flow of fluidtherethrough;

(b) a horizontally positioned support plate member within the verticallyelongated chamber and partitioning the chamber into a plurality ofisolated zones;

(c) a central chamber attached to the support plate member, and having aplurality of first fluid openings spaced in the chamber wall;

(d) an annular chamber having a plurality of second fluid openings inthe inner annular wall of the annular chamber attached to the supportplate member spaced around and apart from the attached central chamberin a manner suflicient to provide between the chambers a first, confinedannular space having a third fluid opening;

(e) a first fluid passageway communicating with the central chamber;

(f) a second fluid passageway communicating with the annular chamber;

(g) a first conduit means attached to the annular chamber having aclosed end spaced apart from the rst annular space, a fourth fluidopening in the conduit wall and an open enclin communication with thethird fluid opening;

(h) a second conduit means, closed at both ends and having a fifth fluidopening in the conduit wall, spaced around and apart from the firstconduit means; and

(i) means for attaching the iirst conduit to the second conduit in amanner sufficient to space the first con duit from the second conduitand to provide a second annular space between the conduits havingcommunication with the fourth fluid opening and fifth fluid opening.

14. The fluid contacting means of claim 13 wherein the first and seconduid openings of the central and annular chambers are in substantiallyaxial alignment.

15. The iiuid contacting means of claim 13 wherein the central chamberand the annular chamber are cylindrical chambers and the tirst fluidopenings and second fluid openings are substantially uniformly spacedand are in substantially axial alignment.

16. The uid contacting means of claim 13 wherein the annular chamber isdivided into a plurality of sectors with each sector containing at leastone of the second openings.

17. The fiuid contacting means of claim 16 wherein each sector is incommunication with an adjoining sector.

18. The contacting means of claim 13 wherein the fourth Huid opening andthe fifth uid opening comprise a slot parallel to the axis of eachconduit.

19. The contacting means of claim 13 wherein the fourth iiuid openingand the iifth uid opening are disaligned.

20. The contacting means of claim 13 wherein the fourth fluid openingand the fifth fluid opening each cornprise a pair of slots parallel tothe axis of each conduit andare about 90 disaligned.

21. The iluid contacting chamber of claim 13 wherein the confinedcentral chamber and the annular chamber are attached below the supportplate member.

22. The fluid contacting chamber of claim 13 wherein the confinedcentral chamber and the annular chamber are attached above the supportplate member.

23. The fiuid contacting chamber of claim 13 wherein the contactingchamber comprises a fluid-solids contacting chamber and each combinationcomprising a support plate member, an attached central chamber, and anattached annular chamber holds and retains particulate solids in aplurality of separate superimposed beds.

24. The fluid contacting means of claim 13 wherein the first uidpassageway comprises conduit means for supplying uid to the centralchamber and the second uid passageway comprises perforate means in thesupport plate member.

25. The fluid contacting means of claim 24 wherein the perforate meanscomprises an outer annular section of the support plate member.

26. The uid contacting means of claim 25 wherein the perforate meanscomprises a plurality of longitudinal rod members transversely attachedto bearing member in a manner suicient to provide a plurality of slotopenings.

27. The iiuid contacting means of claim 26 wherein the longitudinal barmembers have a wedge-shaped crosssection, with the wider portion thereofalong the outer face of the perforate means, resulting in slot openingshaving wedge-shaped cross-section with the wider portion thereof alongthe inner face of the perforate means opening into the annular chamber.

28. The uid contacting chamber of claim 13 wherein the second uidpassageway comprises conduit means for supplying Huid to the annularchamber and the rst iiuid passageway comprises perforate means in thesupport plate member.

29. The tluid contacting means of claim 28 wherein the perforate meanscomprises a plurality of longitudinal rod members transversely attachedto bearing member in a manner sutiicient to provide a plurality of slotopenings.

30. The fiuid contacting means of claim 29 wherein the longitudinal barmembers have a wedge-shaped crosssection with the wider portion thereofalong the outer face of the perforate means, resulting in slot openingshaving wedge-shaped cross-sectionwith the wider portion thereof alongthe inner face of the perforate means opening into the annular chamber.

31. The uid contacting means of claim 13 wherein a perforate means isattached to the second conduit below the fifth fluid openings.

32. The iiuid contacting means of claim 28 wherein the perforate meanscomprises an imperforate center section and a perforate annular sectionaround the center section. j

References Cited UNITED STATES PATENTS 3,598,541 8/ 1971 Hennemuth etal. 23-288 R 3,433,600 3/ 1969 Christensen et al. 23-288 R 3,101,526 8/1963 Paullus et al. 29-163.5 CW

JAMES H. TAYMAN, JR., Primary Examiner U.'S. C1 X.R.

